With increasing development of science and technology as well as industrial and commercial prosperity, people's living standards are gradually increased and the demands on the quality of leisure lives are developed toward sophisticated levels. For example, the hearing effects of sound, the visual changes of light beams or the clarity of images are important issues of the technical development and product development. Moreover, since songs (or music) may provide the function of relaxing the listeners and eliminating stress, songs (or music) are important to the leisure lives. Consequently, a variety of stereo devices are introduced into the market in order to meet the requirements of different users. For example, high-quality stereo devices, stereo devices that produce shocked hearing effects or small-sized portable stereo devices were developed.
Regardless of which type of stereo device is used, the inner space of the stereo device may generate a resonant effect to produce sound. The operating principles of the stereo device will be simply described as follows. Firstly, electric power is supplied to a coil of the stereo device. Consequently, an electric current flows through the coil to generate an electromagnetic field. For example, the frequency of the electromagnetic field is 256 Hz. That is, the number of vibration cycles per second is 256. When an AC power with the frequency of 256 Hz is outputted from the stereo device, the number of times the electric current changes per second is 256. Consequently, the membrane and the coil within the stereo device are subjected to vibration. Due to the vibration of the membrane and the coil, the air within the inner space of the stereo device is vibrated and a resonant effect occurs. In such way, the stereo device can produce sound.
However, a portion of the air may leak out from the inner space of the stereo device. If the amount of air leaking out from the inner space of the stereo device is very large, the resonant effect of the stereo device is adversely affected and the quality of the stereo device is deteriorated.
Therefore, there is a need of providing a stereo device testing method and a stereo device testing system in order to detect a gas leakage condition of the stereo device.